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<body><h1><a href="http://ejohn.org/blog/processingjs/">Processing.js</a></h1>
<h2>PolarToCartesian</h2>

<p>by Daniel Shiffman.  

Convert a polar coordinate (r,theta) to cartesian (x,y):  
x = rcos(theta)
y = rsin(theta)</p>

<p><a href="http://processing.org/learning/basics/polartocartesian.html"><b>Original Processing.org Example:</b> PolarToCartesian</a><br>
<script type="application/processing">
float r;

// Angle and angular velocity, accleration
float theta;
float theta_vel;
float theta_acc;

void setup() {
  size(200,200);
  frameRate(30);
  smooth();
  
  // Initialize all values
  r = 50.0f;
  theta = 0.0f;
  theta_vel = 0.0f;
  theta_acc = 0.0001f;
}

void draw() {
  background(0);
  // Translate the origin point to the center of the screen
  translate(width/2,height/2);
  
  // Convert polar to cartesian
  float x = r * cos(theta);
  float y = r * sin(theta);
  
  // Draw the ellipse at the cartesian coordinate
  ellipseMode(CENTER);
  noStroke();
  fill(200);
  ellipse(x,y,16,16);
  
  // Apply acceleration and velocity to angle (r remains static in this example)
  theta_vel += theta_acc;
  theta += theta_vel;

}
</script><canvas width="200" height="200"></canvas></p>
<div style="height:0px;width:0px;overflow:hidden;"></div>

<pre><b>// All Examples Written by <a href="http://reas.com/">Casey Reas</a> and <a href="http://benfry.com/">Ben Fry</a>
// unless otherwise stated.</b>
float r;

// Angle and angular velocity, accleration
float theta;
float theta_vel;
float theta_acc;

void setup() {
  size(200,200);
  frameRate(30);
  smooth();
  
  // Initialize all values
  r = 50.0f;
  theta = 0.0f;
  theta_vel = 0.0f;
  theta_acc = 0.0001f;
}

void draw() {
  background(0);
  // Translate the origin point to the center of the screen
  translate(width/2,height/2);
  
  // Convert polar to cartesian
  float x = r * cos(theta);
  float y = r * sin(theta);
  
  // Draw the ellipse at the cartesian coordinate
  ellipseMode(CENTER);
  noStroke();
  fill(200);
  ellipse(x,y,16,16);
  
  // Apply acceleration and velocity to angle (r remains static in this example)
  theta_vel += theta_acc;
  theta += theta_vel;

}</pre>
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